NASA were warned to not leave the filled fuel tanks outside in sub-zero conditions overnight, as it would cause the O rings to contract and leak the stored fuel.
So, what did they do…
My initial understanding of the internal construction of the Teves III hydraulic unit was mistaken as I had heeded the words of St.Kirby, that there is a special seal between the high pressure reservoir and the master piston, which could fail and allow pressurised fluid into the master cylinder. (Yes, I was duped too, for a while. There, I’ve admitted it…your turn.)
Upon re-examining the diagram I saw an active return between the boost and master pistons, which means no pressure in that area and also means no seal for St.Kirby and XJSBanger to look at re-manufacturing.
At least XJSBanger was right though when he said these system failures were down to Grandpa’s running their cars with braking systems full of water and flat accumulators.
As a matter of interest when did you see this active return?
There may be a simple O ring/teflon seal on the actual pistons, but nothing to restrict free flow of fluid back to the reservoir.
The Teves III has a significant oversupply of fluid, so a slight leakage back to the reservoir is insignificant and is expected.
The system will still maintain full pressure pressing on the boost piston and feeding rear brake supply.
Do you have a definitive parts guide for the Teves III hydraulic unit? If you have, please share.
The original JagLovers thread where XjsBanger attempted to right Kirberts poor knowledge, yet insistence, but was suckered into believing there was a special seal inside the hydraulic unit.
Teves ABS - Project Refurb - XJ-S - Jag-lovers Forums
That “special seal” is just a piston guide called the Positioning sleeve. The sleeve and spring smooth out ABS feedback into the pedal.
Image from that thread…
As far as whether I have ever rebuilt basic master cylinders…I grew up driving and working on on rubbish quality British manufactured cars…one quickly learns to buy a foreign made car.